Type validator is a type checker for unserialized (untrusted) network objects. Type checker syntax aims to be safe and compact. It can be used, for example, with BitTorrent's bencoded messages to validate untrusted messages from the network.

php-iban is a PHP library for parsing and validating IBAN bank account information. All parts of an IBAN can be retrieved, including country code, checksum, BBAN, financial institution or bank code, and where a fixed-length national system is in use, also branch/sort code and account number. The parser was built using regular expressions to adapt the contents of the official IBAN registry available from SWIFT then only manually modified for a few special cases. Various deficiencies in the initial adaptation have since been rectified, and the current version should be a fairly correct and reliable implementation.

libhtml is a minimal C library for parsing, serializing, and manipulating HTML-4.01-strict and XHTML-1.0-strict documents. You may enjoy this library if you're interested in tight correctness of input and output data.

File upload and validation class is a PHP class that can be used to validate and process uploaded files. It can validate a given uploaded file by checking its MIME type or its original file type, and by checking its file size against a given limit and file type. It currently supports audio, video, PDF, and image file uploads. The class can create a path in the server as well.

xhtml_parte is a class for parsing HTML using regular expressions to validate it and extract parts, given identifier attribute values of the tags that should be extracted. It can also be used to insert and delete tags at specified positions or with certain characteristics.

is_email() is a PHP function that checks the validity of an email address. It tests whether the given address conforms to the followings RFCs: 5321, 5322, 4291, 2821, 2822, 3696, and 1123 (section 2.1).

allowHTML is a PHP class that can be used to filter insecure HTML by following OWASP AntiSamy rules. It can parse HTML documents using DOM document objects and then remove unsafe tags, attributes, and CSS parameters. It uses a configurable whitelist to determine which tags, attributes, and CSS style parameters are allowed. The class may also apply filtering rules defined in a separate AntiSamy XML rules file.

EMF Validation Builder is an Eclipse plugin that automates the validation process at the time of saving. This means that resource problem markers are up to date as soon as you save your model. A dependency table is maintained, which allows the validation process to be re-run when necessary. In particular, the tool can be directly used with ECore model files.

Serene is a validation engine that implements the JAXP 1.3 Validation Framework API for RELAX NG based on an algorithm centered on providing good messages and having a clear handling of ambiguity and conflicts. It has an implementation of the JAXP Validation Framework API for ISO Schematron and support for Schematron markup embedded in RELAX NG schemas.